1. Field of the Invention
This invention relates to soil stabilization.
2. Description of the Prior Art
The prior art discloses many reasons for wishing to stabilize the soil. For example, soil has been stabilized to prevent erosion, to prevent seepage and even to accelerate the rate of seed germination. The military services and others who fly helicopters are interested in stabilizing the soil to prevent dust from being stirred up when a helicopter lands.
Some soil stabilization techniques require the penetration of a stabilizing material deep into the soil. This is true, for example, when it is desired to stabilize soil around a leaking conduit or the like to prevent fluid from leaking out of the conduit. However, most soil stabilization techniques involve the formation of a crust or layer of relatively impervious material on the surface of the soil. These techniques are used to prevent or at least interfere with erosion and are suitable to prevent dust clouds. They differ from each other primarily in what the soil stabilization material is.
Materials used in this latter soil stabilization technique have included natural or synthetic rubber latexes mixed with oil (U.S. Pat. No. 4,028,897); the reaction products of cationic polymer latexes prepared from acrylate polymers and anionic lignins produced by alkali treatment of cellulosic materials (U.S. Pat. No. 3,705,467); mixtures of acrylic emulsion polymer with sodium silicate (U.S. Pat. No. 3,763,072); and aqueous solutions of water soluble salts of polymeric polycarboxylic polyhydroxy acids (U.S. Pat. No. 3,268,002). These aforementioned materials have drawbacks. Among these drawbacks is the fact that they tend to cure slowly. That is, once the material is applied to the soil, it generally takes hours and sometimes days before stabilization is achieved. This tendency toward slow curing is an especially serious drawback when the soil stabilization purpose is dust suppression. In many situations it is desirable to have a helicopter land within minutes or even seconds after the crust-forming materials have been applied. In such situations, the aforementioned materials cure too slowly to be of use. If they have not cured, there is no adhesion of the loose surface of dust, sand, or gravel to the soil beneath so that the dust and sand are easily blown away.